The microstructure,fracture mechanisms,deformation modes,and their correlation with the mechanical properties of Mg-Zn-Gd alloys were analyzed,considering the influence of Y and Nd additions.Increasing Y content and d...The microstructure,fracture mechanisms,deformation modes,and their correlation with the mechanical properties of Mg-Zn-Gd alloys were analyzed,considering the influence of Y and Nd additions.Increasing Y content and decreasing Nd content resulted in an increase in grain size from 17.2 to 29.2μm,and two types of LPSO phases,14 H and 18 R,formed in the alloy.The mechanical properties of the alloys were predominantly influenced by the LPSO phase,with the grain size effect being relatively minor.Based on this analysis,higher Y and lower Nd contents enhanced the tensile strength,yield strength,and elongation of the alloys,with additional improvements observed following solid solution treatment.Changes in Y and Nd content caused a shift in fracture patterns,transitioning from ductile fracture to brittle fracture and then to mixed fracture.Following solid solution treatment,the alloy progressively transitions from intergranular to a combination of ductile and deconvolutional fracture.The deformation modes observed at each stage are as follows:an increase in LPSO phases and twins activates pyramidal slip and suppresses prismatic slip.展开更多
In the present study,experimental and numerical investigations were carried out to examine the behavior of sandwich panels with honeycomb cores.The high velocity impact tests were carried out using a compressed air gu...In the present study,experimental and numerical investigations were carried out to examine the behavior of sandwich panels with honeycomb cores.The high velocity impact tests were carried out using a compressed air gun.A sharp conical nosed projectile was impacted normally and with some offset distance(20 mm and 40 mm).The deformation,failure mode and energy dissipation characteristics were obtained for both kinds of loading.Moreover,the explicit solver was run in Abaqus to create the finite element model.The numerically obtained test results were compared with the experimental to check the accuracy of the modelling.The numerical result was further employed to obtain strain energy dissipation in each element by externally running user-defined code in Abaqus.Furthermore,the influence of inscribe circle diameter and cell wall and face sheet thickness on the energy dissipation,deformation and failure mode was examined.The result found that ballistic resistance and deformation were higher against offset impact compared to the normal impact loading.Sandwich panel impacted at 40 mm offset distance required 3 m/s and 1.9 m/s more velocity than 0 and 20 mm offset distance.Also,increasing the face sheet and wall thickness had a positive impact on the ballistic resistance in terms of a higher ballistic limit and energy absorption.However,inscribe circle diameter had a negative influence on the ballistic resistance.Also,the geometrical parameters of the sandwich structure had a significant influence on the energy dissipation in the different deformation directions.The energy dissipation in plastic work was highest for circumferential direction,regardless of impact condition followed by tangential,radial and axial directions.展开更多
基金Project(2024QN05053)supported by the Natural Science Foundation of Inner Mongolia,ChinaProjects(U24A20106,51931005,52171048)supported by the National Natural Science Foundation of ChinaProject(2020ZDLGY12-02)supported by the Key Industry Innovation Chain Project of Shaanxi Province,China。
文摘The microstructure,fracture mechanisms,deformation modes,and their correlation with the mechanical properties of Mg-Zn-Gd alloys were analyzed,considering the influence of Y and Nd additions.Increasing Y content and decreasing Nd content resulted in an increase in grain size from 17.2 to 29.2μm,and two types of LPSO phases,14 H and 18 R,formed in the alloy.The mechanical properties of the alloys were predominantly influenced by the LPSO phase,with the grain size effect being relatively minor.Based on this analysis,higher Y and lower Nd contents enhanced the tensile strength,yield strength,and elongation of the alloys,with additional improvements observed following solid solution treatment.Changes in Y and Nd content caused a shift in fracture patterns,transitioning from ductile fracture to brittle fracture and then to mixed fracture.Following solid solution treatment,the alloy progressively transitions from intergranular to a combination of ductile and deconvolutional fracture.The deformation modes observed at each stage are as follows:an increase in LPSO phases and twins activates pyramidal slip and suppresses prismatic slip.
文摘In the present study,experimental and numerical investigations were carried out to examine the behavior of sandwich panels with honeycomb cores.The high velocity impact tests were carried out using a compressed air gun.A sharp conical nosed projectile was impacted normally and with some offset distance(20 mm and 40 mm).The deformation,failure mode and energy dissipation characteristics were obtained for both kinds of loading.Moreover,the explicit solver was run in Abaqus to create the finite element model.The numerically obtained test results were compared with the experimental to check the accuracy of the modelling.The numerical result was further employed to obtain strain energy dissipation in each element by externally running user-defined code in Abaqus.Furthermore,the influence of inscribe circle diameter and cell wall and face sheet thickness on the energy dissipation,deformation and failure mode was examined.The result found that ballistic resistance and deformation were higher against offset impact compared to the normal impact loading.Sandwich panel impacted at 40 mm offset distance required 3 m/s and 1.9 m/s more velocity than 0 and 20 mm offset distance.Also,increasing the face sheet and wall thickness had a positive impact on the ballistic resistance in terms of a higher ballistic limit and energy absorption.However,inscribe circle diameter had a negative influence on the ballistic resistance.Also,the geometrical parameters of the sandwich structure had a significant influence on the energy dissipation in the different deformation directions.The energy dissipation in plastic work was highest for circumferential direction,regardless of impact condition followed by tangential,radial and axial directions.
